Abstract
Si-containing hydroxyapatite (SiHAp) particles with 1.67 and 1.95 in Ca/(P+Si) were synthesized by the wet chemical method; 0.08M Si(OC2H5)4 and slurry of 0.5M Ca(OH)2 (pH 10.5) were mixed together, and the mixture was aged for 0 and 24 h. Then, 0.217 or 0.177M H3PO4 solution was dropwisely added to the mixture at a rate of 3ml/min at 80°C. The local structure around Si, P and H in SiHAp was analyzed by solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. After the 29Si NMR analysis, Qn (n=0, 2, 3, 4) structure units were present in the samples derived from the Ca(OH)2 slurry with 0 h aging, and the aging increased the fraction of Q0 content in SiHAp, or it promoted the Si(IV) incorporation into the HAp lattice. In contrast, it suppressed the fractions of the condensed silicate units (Qn (n=2, 3, 4)).
